CN114478879B - Molecular weight regulating method of ultra-high molecular weight polyethylene - Google Patents
Molecular weight regulating method of ultra-high molecular weight polyethylene Download PDFInfo
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- CN114478879B CN114478879B CN202210177281.2A CN202210177281A CN114478879B CN 114478879 B CN114478879 B CN 114478879B CN 202210177281 A CN202210177281 A CN 202210177281A CN 114478879 B CN114478879 B CN 114478879B
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- 239000004699 Ultra-high molecular weight polyethylene Substances 0.000 title claims abstract description 60
- 229920000785 ultra high molecular weight polyethylene Polymers 0.000 title claims abstract description 60
- 238000000034 method Methods 0.000 title claims abstract description 54
- 230000001105 regulatory effect Effects 0.000 title claims abstract description 40
- LFQSCWFLJHTTHZ-UHFFFAOYSA-N Ethanol Chemical compound CCO LFQSCWFLJHTTHZ-UHFFFAOYSA-N 0.000 claims abstract description 83
- VGGSQFUCUMXWEO-UHFFFAOYSA-N Ethene Chemical compound C=C VGGSQFUCUMXWEO-UHFFFAOYSA-N 0.000 claims abstract description 62
- 239000005977 Ethylene Substances 0.000 claims abstract description 62
- 150000001335 aliphatic alkanes Chemical class 0.000 claims abstract description 55
- 239000002904 solvent Substances 0.000 claims abstract description 53
- 239000003054 catalyst Substances 0.000 claims abstract description 46
- 125000005234 alkyl aluminium group Chemical group 0.000 claims abstract description 41
- 238000002156 mixing Methods 0.000 claims abstract description 7
- 238000006116 polymerization reaction Methods 0.000 claims description 46
- 229910052782 aluminium Inorganic materials 0.000 claims description 20
- OKKJLVBELUTLKV-UHFFFAOYSA-N Methanol Chemical compound OC OKKJLVBELUTLKV-UHFFFAOYSA-N 0.000 claims description 15
- VOITXYVAKOUIBA-UHFFFAOYSA-N triethylaluminium Chemical compound CC[Al](CC)CC VOITXYVAKOUIBA-UHFFFAOYSA-N 0.000 claims description 15
- JLTRXTDYQLMHGR-UHFFFAOYSA-N trimethylaluminium Chemical compound C[Al](C)C JLTRXTDYQLMHGR-UHFFFAOYSA-N 0.000 claims description 8
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 claims description 7
- 230000001276 controlling effect Effects 0.000 claims description 7
- LRHPLDYGYMQRHN-UHFFFAOYSA-N N-Butanol Chemical compound CCCCO LRHPLDYGYMQRHN-UHFFFAOYSA-N 0.000 claims description 6
- 238000003756 stirring Methods 0.000 claims description 6
- RTAQQCXQSZGOHL-UHFFFAOYSA-N Titanium Chemical compound [Ti] RTAQQCXQSZGOHL-UHFFFAOYSA-N 0.000 claims description 5
- BDERNNFJNOPAEC-UHFFFAOYSA-N propan-1-ol Chemical compound CCCO BDERNNFJNOPAEC-UHFFFAOYSA-N 0.000 claims description 5
- 229910052719 titanium Inorganic materials 0.000 claims description 5
- 239000010936 titanium Substances 0.000 claims description 5
- 238000010438 heat treatment Methods 0.000 claims description 4
- CNWZYDSEVLFSMS-UHFFFAOYSA-N tripropylalumane Chemical compound CCC[Al](CCC)CCC CNWZYDSEVLFSMS-UHFFFAOYSA-N 0.000 claims description 4
- 125000004432 carbon atom Chemical group C* 0.000 claims description 3
- MYBJXSAXGLILJD-UHFFFAOYSA-N diethyl(methyl)alumane Chemical compound CC[Al](C)CC MYBJXSAXGLILJD-UHFFFAOYSA-N 0.000 claims description 3
- SQBBHCOIQXKPHL-UHFFFAOYSA-N tributylalumane Chemical compound CCCC[Al](CCCC)CCCC SQBBHCOIQXKPHL-UHFFFAOYSA-N 0.000 claims description 3
- MCULRUJILOGHCJ-UHFFFAOYSA-N triisobutylaluminium Chemical compound CC(C)C[Al](CC(C)C)CC(C)C MCULRUJILOGHCJ-UHFFFAOYSA-N 0.000 claims description 3
- 238000001816 cooling Methods 0.000 claims description 2
- ORYGRKHDLWYTKX-UHFFFAOYSA-N trihexylalumane Chemical compound CCCCCC[Al](CCCCCC)CCCCCC ORYGRKHDLWYTKX-UHFFFAOYSA-N 0.000 claims description 2
- 230000037048 polymerization activity Effects 0.000 abstract description 24
- 150000002148 esters Chemical class 0.000 abstract description 3
- 230000000379 polymerizing effect Effects 0.000 abstract description 2
- BLRPTPMANUNPDV-UHFFFAOYSA-N Silane Chemical compound [SiH4] BLRPTPMANUNPDV-UHFFFAOYSA-N 0.000 abstract 1
- 229910000077 silane Inorganic materials 0.000 abstract 1
- VLKZOEOYAKHREP-UHFFFAOYSA-N n-Hexane Chemical compound CCCCCC VLKZOEOYAKHREP-UHFFFAOYSA-N 0.000 description 29
- 239000004698 Polyethylene Substances 0.000 description 13
- 238000006243 chemical reaction Methods 0.000 description 13
- -1 Poly ethylene Polymers 0.000 description 10
- 150000001298 alcohols Chemical class 0.000 description 9
- 229920000573 polyethylene Polymers 0.000 description 9
- 230000000694 effects Effects 0.000 description 8
- 239000000047 product Substances 0.000 description 7
- 238000004519 manufacturing process Methods 0.000 description 6
- 239000002245 particle Substances 0.000 description 6
- 230000000052 comparative effect Effects 0.000 description 5
- 238000002360 preparation method Methods 0.000 description 5
- 239000000126 substance Substances 0.000 description 5
- NIQCNGHVCWTJSM-UHFFFAOYSA-N Dimethyl phthalate Chemical compound COC(=O)C1=CC=CC=C1C(=O)OC NIQCNGHVCWTJSM-UHFFFAOYSA-N 0.000 description 4
- 239000011347 resin Substances 0.000 description 4
- 229920005989 resin Polymers 0.000 description 4
- 230000008901 benefit Effects 0.000 description 3
- 230000033228 biological regulation Effects 0.000 description 3
- 239000000463 material Substances 0.000 description 3
- 230000035945 sensitivity Effects 0.000 description 3
- 150000004756 silanes Chemical class 0.000 description 3
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 3
- 230000015572 biosynthetic process Effects 0.000 description 2
- 230000006583 body weight regulation Effects 0.000 description 2
- 238000006555 catalytic reaction Methods 0.000 description 2
- JJQZDUKDJDQPMQ-UHFFFAOYSA-N dimethoxy(dimethyl)silane Chemical compound CO[Si](C)(C)OC JJQZDUKDJDQPMQ-UHFFFAOYSA-N 0.000 description 2
- FBSAITBEAPNWJG-UHFFFAOYSA-N dimethyl phthalate Natural products CC(=O)OC1=CC=CC=C1OC(C)=O FBSAITBEAPNWJG-UHFFFAOYSA-N 0.000 description 2
- 229960001826 dimethylphthalate Drugs 0.000 description 2
- 238000005516 engineering process Methods 0.000 description 2
- 229920001903 high density polyethylene Polymers 0.000 description 2
- 239000004700 high-density polyethylene Substances 0.000 description 2
- 229920000642 polymer Polymers 0.000 description 2
- 238000003786 synthesis reaction Methods 0.000 description 2
- 238000012360 testing method Methods 0.000 description 2
- VYZAMTAEIAYCRO-UHFFFAOYSA-N Chromium Chemical compound [Cr] VYZAMTAEIAYCRO-UHFFFAOYSA-N 0.000 description 1
- 241000282326 Felis catus Species 0.000 description 1
- UFHFLCQGNIYNRP-UHFFFAOYSA-N Hydrogen Chemical compound [H][H] UFHFLCQGNIYNRP-UHFFFAOYSA-N 0.000 description 1
- 238000005299 abrasion Methods 0.000 description 1
- 238000010521 absorption reaction Methods 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- 229910052804 chromium Inorganic materials 0.000 description 1
- 239000011651 chromium Substances 0.000 description 1
- 238000010276 construction Methods 0.000 description 1
- 238000005336 cracking Methods 0.000 description 1
- 230000007547 defect Effects 0.000 description 1
- 239000006185 dispersion Substances 0.000 description 1
- 150000002170 ethers Chemical class 0.000 description 1
- 239000012467 final product Substances 0.000 description 1
- 229910052739 hydrogen Inorganic materials 0.000 description 1
- 239000001257 hydrogen Substances 0.000 description 1
- 239000012535 impurity Substances 0.000 description 1
- 150000002632 lipids Chemical class 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 231100000956 nontoxicity Toxicity 0.000 description 1
- 238000004806 packaging method and process Methods 0.000 description 1
- 239000003208 petroleum Substances 0.000 description 1
- 230000002035 prolonged effect Effects 0.000 description 1
- 239000002994 raw material Substances 0.000 description 1
- 238000006467 substitution reaction Methods 0.000 description 1
- 238000010998 test method Methods 0.000 description 1
- 239000004753 textile Substances 0.000 description 1
- 238000004260 weight control Methods 0.000 description 1
Classifications
-
- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08F—MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS
- C08F110/00—Homopolymers of unsaturated aliphatic hydrocarbons having only one carbon-to-carbon double bond
- C08F110/02—Ethene
-
- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08F—MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS
- C08F2500/00—Characteristics or properties of obtained polyolefins; Use thereof
- C08F2500/01—High molecular weight, e.g. >800,000 Da.
-
- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08F—MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS
- C08F2500/00—Characteristics or properties of obtained polyolefins; Use thereof
- C08F2500/18—Bulk density
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
- Y02P20/00—Technologies relating to chemical industry
- Y02P20/50—Improvements relating to the production of bulk chemicals
- Y02P20/52—Improvements relating to the production of bulk chemicals using catalysts, e.g. selective catalysts
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- Chemical & Material Sciences (AREA)
- Health & Medical Sciences (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Medicinal Chemistry (AREA)
- Polymers & Plastics (AREA)
- Organic Chemistry (AREA)
- Transition And Organic Metals Composition Catalysts For Addition Polymerization (AREA)
- Addition Polymer Or Copolymer, Post-Treatments, Or Chemical Modifications (AREA)
Abstract
The invention provides a molecular weight regulating method of ultra-high molecular weight polyethylene, which comprises the following steps: mixing ethylene, Z-N catalyst, alkane solvent with dispersed alkyl aluminum and alcohol with different mass, and polymerizing to obtain ultra-high molecular weight polyethylene with different molecular weight. The invention solves the problems of obviously reduced polymerization activity and small molecular weight regulating range of the existing ester or silane regulator by adopting alcohol as the molecular weight regulator. The invention can regulate and control the molecular weight of the product to selectively synthesize the ultra-high molecular weight polyethylene with the molecular weight of 150-1000 ten thousand viscosity average molecular weight, and has simple, convenient and safe operation; in addition, the molecular weight of the product is adjustable, and the quality of other aspects of the product is not reduced.
Description
Technical Field
The invention relates to the technical field of ultra-high molecular weight polyethylene, in particular to a molecular weight regulating method of ultra-high molecular weight polyethylene.
Background
Ultra high molecular weight polyethylene (Ultra High Molecule Weight Poly ethylene, abbreviated as UHMWPE) generally refers to polyethylene having a linear structure with a viscosity average molecular weight greater than 150 ten thousand, and generally has a molecular weight ten times that of conventional High Density Polyethylene (HDPE). UHMWPE has the advantages of small friction coefficient, low abrasion, excellent chemical resistance, impact resistance, sanitation, no toxicity and the like, has good stress cracking resistance and the like, and is widely applied to the fields of textile, papermaking, packaging, transportation, sports, transportation, petroleum, construction, medical treatment and the like.
As UHMWPE synthesis technology advances and evolves, the synthesis of UHMWPE tends to progress specifically. In order to improve the wear resistance or higher strength and modulus properties of UHMWPE materials, it is necessary to use UHMWPE resins having a relatively large molecular weight (typically > 500 tens of thousands). At present, catalysts used for UHMWPE production mainly comprise Z-N type catalysts, chromium type catalysts, metallocene type catalysts and the like, wherein the Z-N type catalysts are the most widely applied and mature technology. The Z-N type catalyst is mainly a carrier type high-efficiency catalyst, and the performance of the catalyst can be improved by adding other components, such as improving the activity of the catalyst, improving the bulk density and molecular weight of the product, regulating the morphology of resin particles, and the like.
CN104558294a discloses an ultra-high molecular weight polyethylene catalyst and a preparation method thereof, and in the patent, an internal electron donor is added to increase the molecular weight of UHMWPE resin in the preparation process of a Z-N catalyst, and the molecular weight of UHMWPE resin is regulated by regulating the dosage of the internal electron donor;
CN108203481a discloses a method for producing ultra-high molecular weight polyethylene by catalytic reaction, which comprises adding external electron donor (silanes, lipids) in the presence of main catalyst and cocatalyst to perform polymerization reaction. The molecular weight of the ultra-high molecular weight polyethylene is regulated by adding the external electron donor. In addition, the molecular weight is regulated by hydrogen or reducing the polymerization reaction temperature, but the methods for regulating the molecular weight have the problems of complex process, inconvenient operation, small molecular weight regulating range, obvious reduction of polymerization activity and the like.
Therefore, there is a need to develop a more convenient and sensitive method of regulating the molecular weight of ultra high molecular weight polyethylene.
Disclosure of Invention
In order to solve the technical problems, the invention provides a molecular weight regulating method of ultra-high molecular weight polyethylene, which can regulate and control the molecular weight of a product to selectively synthesize the ultra-high molecular weight polyethylene with the molecular weight of 150-1000 ten thousand viscosity average molecular weight by adding alcohols into a polymerization reaction system, and the ultra-high molecular weight polyethylene and the added alcohols have obvious positive correlation, thus providing a simple and safe process for regulating and controlling the molecular weight of the ultra-high molecular weight polyethylene.
To achieve the purpose, the invention adopts the following technical scheme:
the invention provides a molecular weight regulating method of ultra-high molecular weight polyethylene, which comprises the following steps: mixing ethylene, Z-N catalyst, alkane solvent with dispersed alkyl aluminum and alcohol with different mass, and polymerizing to obtain ultra-high molecular weight polyethylene with different molecular weight.
The molecular weight regulating method of the ultra-high molecular weight polyethylene provided by the invention discovers that the molecular weight of the ultra-high molecular weight polyethylene has a good positive correlation with the molecular weight of the product, so that the molecular weight regulation of polyethylene can be realized by adding a trace amount of alcohol substances, the method can be suitable for the application range of polyethylene with different ultra-high molecular weights, the defect that the prior art can generally regulate the molecular weight only in a narrow range is overcome, the regulating mode is very simple, only alcohols are needed to be added in the polymerization reaction, and the time of the original reaction does not need to be prolonged because the influence of the addition of the substances on the polymerization activity is small, and the production efficiency and the yield are not influenced.
Compared with esters, ethers or silanes, the invention has the advantages of wide molecular weight adjustment and high reaction activity, and has a significantly wider industrial application range, wherein the viscosity average molecular weight of the ultra-high molecular weight polyethylene can be correspondingly adjusted from about 150W to 1000W for alcohols of 0.1-300 ppm, the adjustment range is large, and the sensitivity to the alcohols is high.
Preferably, the alkylaluminum is any one or a combination of at least two of trimethylaluminum, triethylaluminum, tripropylaluminum, triisobutylaluminum, tri-n-butylaluminum, triisopentylaluminum, trihexylaluminum, triisohexylaluminum or diethylmethylaluminum, wherein typical but non-limiting combinations are combinations of trimethylaluminum and triethylaluminum, combinations of trimethylaluminum and tripropylaluminum, combinations of tripropylaluminum and triethylaluminum, combinations of triisobutylaluminum and triethylaluminum, and combinations of diethylmethylaluminum and tri-n-butylaluminum, preferably triethylaluminum.
Preferably, the Z-N catalyst accounts for 0.001 to 0.003% of the total ethylene feed, and may be, for example, 0.001%, 0.0015%, 0.002%, 0.0025%, or 0.003%, etc., but is not limited to the recited values, and other values not recited in the range are equally applicable.
Preferably, the Z-N catalyst accounts for 1 to 10% of the total mass of the aluminum alkyl, for example, 1%, 2%, 3%, 4%, 5%, 6%, 8%, 9% or 10%, etc., but is not limited to the recited values, and other non-recited values within this range are equally applicable.
Preferably, the alcohol comprises any one or a combination of at least two of methanol, ethanol, propanol or butanol, wherein typical but non-limiting combinations are combinations of methanol and ethanol, propanol and ethanol, methanol and propanol, butanol and ethanol.
Preferably, the alcohol accounts for 0.1 to 300ppm of the total mass of the alkane solvent, and may be, for example, 0.1ppm, 30ppm, 60ppm, 100ppm, 130ppm, 160ppm, 200ppm, 230ppm, 260ppm, 300ppm, or the like, but is not limited to the recited values, and other non-recited values within this range are equally applicable.
The invention further preferably selects the adding amount range of the alcohol adjusting molecular weight in the above range, and can avoid the influence on the reaction activity when the adding amount of the alcohol is too high, thereby simultaneously guaranteeing the production efficiency and the production quality and guaranteeing the economic benefit of production from two aspects.
Preferably, the alkane solvent includes any one or a combination of at least two of alkanes having 5 to 10 carbon atoms, and the carbon atoms may be, for example, 5, 6, 7, 8, 9 or 10, etc., preferably n-hexane.
As a preferable technical scheme of the invention, the molecular weight regulating method comprises the following steps:
(1) Mixing a first part of alkyl aluminum and a first part of alkane solvent, and stirring at a first temperature to obtain an alkane solvent in which the alkyl aluminum is dispersed;
(2) Simultaneously introducing a second part of alkyl aluminum with a Z-N catalyst and a second part of alkane solvent into the alkane solvent in which the alkyl aluminum is dispersed, adding alcohols, and heating to a second temperature;
(3) Introducing ethylene into the system in the step (2), pressurizing, and carrying out polymerization reaction to obtain the ultra-high molecular weight polyethylene with different molecular weights.
The invention further preferably adopts the steps to carry out the mixing and the reaction of materials, wherein the first part of alkyl aluminum and the first part of alkane solvent are mixed firstly, so that the uniform dispersion of the alkyl aluminum is more facilitated, impurities such as moisture and the like in the alkane solvent are eliminated, the polymerization activity and the stability are improved, and the Z-N catalyst, the second part of alkyl aluminum and the second part of alkane solvent are simultaneously added, so that the dosage of the alkyl aluminum directly acting on the catalyst is favorably controlled, the polymerization stability is favorably improved, and finally, the alcohols are added, so that the precise regulation and control of the molecular weight are more favorably realized.
Preferably, in the step (1), the first portion of the aluminum alkyl accounts for 0.01 to 0.02% of the mass of the first portion of the alkane solvent, and may be, for example, 0.01%, 0.012%, 0.013%, 0.014%, 0.015%, 0.016% or 0.02%, etc., but not limited to the recited values, and other non-recited values within the range are equally applicable.
The first temperature is preferably 70 to 80 ℃, and may be, for example, 70 ℃, 72 ℃, 73 ℃, 74 ℃,75 ℃, 76 ℃, 77 ℃, 78 ℃, 79 ℃,80 ℃, or the like, but is not limited to the values recited, and other values not recited in the range are equally applicable.
The stirring time at the first temperature is preferably 0.5 to 1.5 hours, and may be, for example, 0.5 hours, 0.7 hours, 0.8 hours, 0.9 hours, 1 hours, 1.1 hours, 1.2 hours, 1.3 hours, 1.4 hours, or 1.5 hours, etc., but not limited to the recited values, and other non-recited values within this range are equally applicable.
Preferably, the first portion of the alkane solvent in the step (1) accounts for 70-89% of the total alkane solvent, for example, 70%, 73%, 75%, 77%, 79%, 81%, 83%, 85%, 87% or 89%, etc., but not limited to the recited values, and other non-recited values within the range are equally applicable.
Preferably, the first portion of the aluminum alkyl accounts for 60-70% of the total aluminum alkyl, for example, 60%, 62%, 63%, 64%, 65%, 66%, 67%, 68%, 69% or 70%, etc., but is not limited to the recited values, and other non-recited values within this range are equally applicable.
Preferably, the second portion of the alkane solvent in the step (2) accounts for 11-30% of the total alkane solvent, for example, 11%, 14%, 16%, 18%, 20%, 22%, 24%, 26%, 28% or 30%, etc., but not limited to the recited values, and other non-recited values within the range are equally applicable.
Preferably, the second portion of the aluminum alkyl accounts for 30-40% of the total aluminum alkyl, for example, 30%, 32%, 33%, 34%, 35%, 36%, 37%, 38%, 39% or 40%, etc., but is not limited to the recited values, and other non-recited values within the range are equally applicable.
Preferably, the molar ratio of aluminum to titanium in the components of the Z-N catalyst and the aluminum alkyl total is 1 (100-500), and can be, for example, 1:100, 1:150, 1:200, 1:250, 1:300, 1:350, 1:400, 1:450, or 1:500, etc.
Preferably, the molar ratio of aluminum to titanium in the components of the Z-N catalyst to the second portion of alkylaluminum is 1 (50-300), and may be, for example, 1:50, 1:100, 1:150, 1:200, or 1:300, etc
The present invention is preferably carried out with the catalyst of CN 111333755A for the Z-N catalyst and/or with the catalyst of CN 111499777A.
The invention is preferably carried out by using the Z-N catalyst, and the effective adjustment of the molecular weight of the ultra-high molecular weight polyethylene by alcohols can be realized under the catalyst system.
The second temperature is preferably 50 to 65 ℃, and may be, for example, 50 ℃, 52 ℃, 54 ℃, 55 ℃, 57 ℃, 59 ℃,60 ℃, 62 ℃, 64 ℃, or 65 ℃, etc., but is not limited to the recited values, and other values not recited in the range are equally applicable.
The pressure of the polymerization reaction in the step (3) is preferably 0.6 to 0.7MPa, and may be, for example, 0.6MPa, 0.62MPa, 0.63MPa, 0.64MPa, 0.65MPa, 0.66MPa, 0.67MPa, 0.68MPa, 0.69MPa or 0.7MPa, etc., but not limited to the values recited, and other values not recited in the range are equally applicable.
The polymerization reaction temperature is preferably 60 to 80 ℃, and may be 60 ℃, 63 ℃, 65 ℃, 67 ℃, 69 ℃, 72 ℃, 74 ℃, 76 ℃, 78 ℃,80 ℃ or the like, for example, but is not limited to the values recited, and other values not recited in the range are equally applicable.
Preferably, the suction is performed after the polymerization reaction in step (3) is completed.
Preferably, the pressure of the suction pressure is 0.6 to 0.7MPa, for example, 0.6MPa, 0.61MPa, 0.62MPa, 0.63MPa, 0.64MPa, 0.68MPa, 0.7MPa, or the like. The suction pressure refers to the pressure of the polymerization reaction which is kept for a period of time.
Preferably, the time for the suction is 5 to 15min, for example, 5min, 7min, 8min, 9min, 10min, 11min, 12min, 13min, 14min or 15min, etc., but not limited to the recited values, and other values not recited in the range are equally applicable.
Preferably, the initial flow rate of ethylene in the step (3) is 500 to 2000g/h, and after the polymerization pressure is reached, the flow rate is controlled to maintain the polymerization pressure constant, and for example, 500g/h, 600g/h, 800g/h, 1000g/h, 1100g/h, 1300g/h, 1500g/h, 1600g/h, 1800g/h, 2000g/h, etc., but the present invention is not limited to the above-mentioned values, and other values not mentioned in the above range are equally applicable.
Preferably, the ethylene is introduced in two stages, a first stage and a second stage.
Preferably, the ethylene flow rate in the first stage is 500 to 700g/h, for example, 500g/h, 520g/h, 540g/h, 560g/h, 580g/h, 610g/h, 630g/h, 650g/h, 670g/h or 700g/h, etc., but not limited to the recited values, and other non-recited values within this range are equally applicable.
Preferably, the ethylene feed amount in the first stage is 3 to 5wt% of the total ethylene feed amount, and may be, for example, 3wt%, 3.3wt%, 3.5wt%, 3.7wt%, 3.9wt%, 4.2wt%, 4.4wt%, 4.6wt%, 4.8wt% or 5wt%, etc., but not limited to the recited values, and other non-recited values within this range are equally applicable.
Preferably, the initial flow rate of ethylene in the second section is 1500-2000 g/h, and after the pressure of the polymerization reaction is reached, the flow rate is regulated to stabilize the pressure of the polymerization reaction. For example, 1500g/h, 1556g/h, 1612g/h, 1667g/h, 1723g/h, 1778g/h, 1834g/h, 1889g/h, 1945g/h or 2000g/h may be used, but the present invention is not limited to the values recited, and other values not recited in the range are equally applicable.
Preferably, the ethylene feed amount in the second stage is 95-97 wt% of the total ethylene feed amount, and may be, for example, 95wt%, 95.3wt%, 95.5wt%, 95.7wt%, 95.9wt%, 96.2wt%, 96.4wt%, 96.6wt%, 96.8wt%, 97wt%, etc., but is not limited to the recited values, and other non-recited values within the range are equally applicable.
The invention preferably introduces ethylene in two sections with different flow rates, wherein when the ethylene is introduced in the first section with small flow rate, the active center of the system can be slowly nucleated, the reaction is stable, the temperature of the system is controlled to be stable, and the ethylene is introduced in the second section with large flow rate, so that the reaction system can quickly reach the pressure required by the reaction, and the performance of the final product is improved.
Preferably, the ultra-high molecular weight polyethylene and the alcohols have a positive correlation linear relation, wherein the positive correlation coefficient of the molecular weight (ten thousand) of the ultra-high molecular weight polyethylene and the concentration (ppm) of the ethanol is between 1.1 and 1.3, for example, 1.2523, so that the possibility of conveniently and sensitively adjusting the molecular weight of the ultra-high molecular weight polyethylene is provided.
As a preferable technical scheme of the invention, the molecular weight regulating method comprises the following steps:
(1) Mixing a first part of alkyl aluminum and a first part of alkane solvent, wherein the first part of alkyl aluminum accounts for 0.01-0.02% of the mass of the first part of alkane solvent, stirring for 0.5-1.5 h at 70-80 ℃, the first part of alkane solvent accounts for 70-89% of the total alkane solvent, and the first part of alkyl aluminum accounts for 60-70% of the total alkyl aluminum, so as to obtain the alkane solvent dispersed with the alkyl aluminum;
(2) Simultaneously introducing a second part of alkyl aluminum with a Z-N catalyst and a second part of alkane solvent into the alkane solvent in which the alkyl aluminum is dispersed, wherein the second part of alkane solvent accounts for 11-30% of the total alkane solvent, the second part of alkyl aluminum accounts for 30-40% of the total alkyl aluminum, the molar ratio of aluminum to titanium in the total components of the Z-N catalyst and the alkyl aluminum is 1 (100-500), the Z-N catalyst accounts for 1-10% of the total alkyl aluminum, adding alcohol with the total alkane solvent weight of 0.1-300 ppm, and heating to 50-65 ℃;
(3) Introducing ethylene into the system of the step (2) in two sections, wherein the flow of the ethylene in the first section is 500-700 g/h, and the feeding amount of the ethylene in the first section accounts for 3-5 wt% of the total feeding amount of the ethylene; regulating the flow to the second section, wherein the initial flow of ethylene in the second section is 1500-2000 g/h, and regulating the flow after reaching the pressure of the polymerization reaction to stabilize the pressure of the polymerization reaction; the feeding amount of ethylene in the second section accounts for 95-97 wt% of the total feeding amount of ethylene, and the Z-N catalyst is controlled to account for 0.003-0.007% of the total feeding amount of ethylene and then ethylene feeding is stopped; and after the feeding is finished, maintaining the pressure of the polymerization reaction at 0.6-0.7 MPa and at 60-80 ℃ for polymerization reaction, maintaining the suction pressure at 60-80 ℃ for 5-15 min after the polymerization reaction is finished, decompressing and cooling to obtain the ultra-high molecular weight polyethylene with different molecular weights.
Compared with the prior art, the invention has at least the following beneficial effects:
(1) The molecular weight regulating method of the ultra-high molecular weight polyethylene solves the problem of stable regulation of the molecular weight in the existing ultra-high molecular weight polyethylene polymerization process, and provides a method which is simple and safe to operate and can stably regulate the molecular weight of the polymer;
(2) The molecular weight of the ultra-high molecular weight polyethylene can be selectively regulated and controlled by adding a trace amount of alcohol substances, the molecular weight of the ultra-high molecular weight polyethylene and the addition amount of ethanol are in obvious linear positive correlation in the range of 0-300 ppm, wherein the fitted R 2 Up to 0.9961, the molecular weight is adjusted to 150-1000 ten thousand, the linear slope of adjustment is more than 1.12, the influence on the reaction activity is small, and the polymerization activity can still keep 18000 g.PE/g.cat.h -1 The above can achieve a molecular weight of 600w or more while maintaining the polymerization activity 30000 g.PE/g.cat.h -1 The above; the gradient of the decrease of the polymerization activity is within-40, the particle size of the obtained ultra-high molecular weight polyethylene is proper, D 50 Between 98 and 114 mu m, the bulk density is between 0.37 and 0.44g/cm 3 Between them;
(3) The molecular weight regulating method of the ultra-high molecular weight polyethylene provided by the invention does not reduce other properties of the ultra-high molecular weight polyethylene such as particle size, bulk density and the like.
Drawings
FIG. 1 is a graph showing the relationship between the molecular weight of the ultra-molecular weight polyethylene and the concentration of ethanol in example 3 of the present invention.
FIG. 2 is a graph showing the polymerization activity versus ethanol concentration at various temperatures according to the present invention (other conditions are the same as in example 3).
Detailed Description
To facilitate understanding of the present invention, examples are set forth below. It will be apparent to those skilled in the art that the examples are merely to aid in understanding the invention and are not to be construed as a specific limitation thereof.
Example 1
The embodiment provides a preparation method of ultra-high molecular weight polyethylene, which comprises the following steps:
(1) 20ml of triethylaluminum (1 mol/L, the same applies hereinafter) and 4L of hexane were mixed and stirred at 70℃for 0.5 hours to obtain an alkane solvent in which triethylaluminum was dispersed;
(2) Simultaneously, 10ml of triethylaluminum solution (1 mol/L) (which is uniformly mixed) with 20mg of Z-N catalyst (catalyst A in CN 111499777A) and 0.5L of hexane are introduced into an alkane solvent in which triethylaluminum is dispersed, then ethanol with the total mass of 20ppm of hexane is added, and the temperature is raised to 50 ℃;
(3) Introducing ethylene into the system in the step (2) in two sections, wherein the flow rate of the ethylene in the first section is 500g/h, and the feeding amount of the ethylene in the first section is 40g; regulating the flow to the second section, wherein the initial flow of ethylene in the second section is 1500g/h, and regulating the flow to stabilize the pressure of the polymerization reaction after reaching the pressure (0.6 MPa) of the polymerization reaction, wherein the flow is about 500g/h, the feeding amount of ethylene in the second section is 1160g, and the accumulated feeding amount is 1200g; after the feeding is finished, the pressure of the polymerization reaction is kept at 0.6MPa, the reaction is controlled by controlling the flow of ethylene and the temperature of a water bath, the polymerization reaction is carried out at 60 ℃, the pressure is absorbed for 5min at 60 ℃ after the polymerization reaction is finished, and then the pressure is relieved and the temperature is reduced, so that the ultra-high molecular weight polyethylene is obtained.
The molecular weight was controlled in example 1, and the bulk density, viscosity average molecular weight and D50 of the product molecular weight polyethylene were measured by varying the concentration of ethanol, and the results are shown in Table 1.
TABLE 1
The relationship between the viscosity average molecular weight and the ethanol concentration of 0 to 300ppm was linearly fitted to find that y=1.9051x+343.81, R 2 Linear fitting of the above relation between polymerization activity and ethanol concentration of 0 to 300ppm was performed to find y= -23.927x+24855, r 2 ＝0.9312。
Example 2
The embodiment provides a preparation method of ultra-high molecular weight polyethylene, which comprises the following steps:
(1) 40ml of triethylaluminum (1 mol/L, the same applies hereinafter) and 5L of hexane were mixed and stirred at 80℃for 1.5 hours to obtain an alkane solvent in which triethylaluminum was dispersed;
(2) Simultaneously, 20ml of triethylaluminum solution (1 mol/L) (which is uniformly mixed) with 30mg of Z-N catalyst (catalyst B in CN 111499777A) and 2L of hexane are introduced into an alkane solvent in which the triethylaluminum is dispersed, then 200ppm of ethanol with the total mass of hexane is added, and the temperature is raised to 70 ℃;
(3) Introducing ethylene into the system in the step (2) in two sections, wherein the flow rate of the ethylene in the first section is 700g/h, and the feeding amount of the ethylene in the first section is 60g; regulating the flow to the second section, wherein the initial flow of ethylene in the second section is 1800g/h, regulating the flow to stabilize the pressure of the polymerization reaction after reaching the pressure of 0.65MPa, and regulating the flow to about 1300g/h, wherein the feeding amount of ethylene in the second section is 1140g, and the accumulated feeding amount is 1200g; after the feeding is finished, the pressure of the polymerization reaction is kept at 0.65MPa, the reaction is controlled by controlling the flow of ethylene and the temperature of a water bath, the polymerization reaction is carried out at 80 ℃, the pressure absorption at 80 ℃ is maintained for 15min after the polymerization reaction is finished, and then the pressure is relieved and the temperature is reduced, so that the ultra-high molecular weight polyethylene is obtained.
The molecular weight control in example 2 was measured by varying the concentration of ethanol to measure the bulk density, viscosity average molecular weight and D50 of the product molecular weight polyethylene, and the results are shown in Table 2.
TABLE 2
The relationship between the viscosity average molecular weight and the ethanol concentration of 0 to 300ppm was linearly fitted to find that y=1.16019x+152.39, R 2 Linear fitting of the above relation between polymerization activity and ethanol concentration of 0 to 300ppm was performed with = 0.9968, and found that y= -39 869x+46436, r 2 ＝0.9817。
Example 3
The embodiment provides a preparation method of ultra-high molecular weight polyethylene, which comprises the following steps:
(1) 32ml of trimethylaluminum (1 mol/L, the same applies below) and 5L of hexane were mixed and stirred at 75℃for 1 hour to obtain an alkane solvent in which trimethylaluminum was dispersed;
(2) Simultaneously, 16ml of trimethylaluminum solution (1 mol/L) (which is uniformly mixed) with 15mg of Z-N catalyst (catalyst B in CN 111499777A) and 1L of hexane are introduced into an alkane solvent in which trimethylaluminum is dispersed, then 50ppm of ethanol with the total mass of hexane is added, and the temperature is raised to 65 ℃;
(3) Introducing ethylene into the system in the step (2) in two sections, wherein the flow rate of the ethylene in the first section is 600g/h, and the feeding amount of the ethylene in the first section is 50g; regulating the flow to the second section, wherein the initial flow of ethylene in the second section is 2000g/h, regulating the flow to stabilize the pressure of the polymerization reaction after reaching the pressure of the polymerization reaction, and regulating the flow to about 700g/h, wherein the feeding amount of ethylene in the second section is 1150g, and the accumulated feeding amount is 1200g; after the feeding is finished, the pressure of the polymerization reaction is maintained at 0.7MPa, the reaction is controlled by controlling the flow of ethylene and the temperature of a water bath, the polymerization reaction is carried out at 75 ℃, the pressure suction at 75 ℃ is maintained for 10min after the polymerization reaction is finished, and then the pressure is relieved and the temperature is reduced, so that the ultra-high molecular weight polyethylene is obtained.
The molecular weight was controlled in example 3, and the bulk density, viscosity average molecular weight and D50 of the product molecular weight polyethylene were measured by varying the concentration of ethanol, and the results are shown in Table 3.
TABLE 3 Table 3
As can be seen from Table 3 and FIG. 1, the molecular weight of the ultra-high molecular weight polyethylene and the amount of ethanol added are in a significantly linear positive correlation in the range of 0 to 400ppm, wherein R is fitted 2 The gradient is up to 0.9949 and 1.2523, which shows that the fitting effect is excellent, the linear relation between the two is obviously established, and the adjusting sensitivity of the ethanol to the ultra-high molecular weight polyethylene is high.
The relation between the polymerization activity and the ethanol concentration of 0-300 ppm is subjected to linear fitting, and y= -28.3833x+41406 and R are found 2 ＝0.9748。
The effect on polymerization activity was observed by adjusting only the temperature based on example 3, and the results are shown in FIG. 2, and it can be seen from FIG. 2 that the decrease in polymerization activity at different polymerization temperatures was small.
Example 4
This example provides a method for molecular weight adjustment of ultra-high molecular weight polyethylene, which is the same as example 3 except that ethanol is replaced with methanol, and the results are shown in table 4.
TABLE 4 Table 4
The relationship between the viscosity average molecular weight and the ethanol concentration of 0 to 300ppm was linearly fitted to find that y=1.1717x+261.27, r 2 =0.998, and the relation between the polymerization activity and the ethanol concentration of 0 to 300ppm was linearly determinedFitting, found y= -39.721x+44295, r 2 ＝0.9976。
Example 5
This example provides a method for molecular weight adjustment of ultra-high molecular weight polyethylene, which is the same as example 3 except that ethanol is replaced with propanol, and the results are shown in table 5.
TABLE 5
Linear fitting of the above relationship between the viscosity average molecular weight and the ethanol concentration of 0 to 300ppm revealed that y=1.1294x+253.24, r 2 Linear fitting of the above relation between polymerization activity and ethanol concentration of 0 to 300ppm was performed with = 0.9966, and found that y= -22 865x+37688, r 2 ＝0.8951。
As can be seen from tables 1 to 5, the alcohol substance provided by the invention has excellent regulation effect on the ultra-high molecular weight polyethylene and less reduction of polymerization activity, wherein the molecular weight regulation range is 150-1000 ten thousand, the linear slope is regulated to be more than 1.12, and the polymerization activity can still keep 18000 g.PE/g.cat.h -1 The gradient of the decrease of the polymerization activity is within-40, the particle size of the obtained ultra-high molecular weight polyethylene is proper, D 50 Between 98 and 114 mu m, the bulk density is between 0.37 and 0.44g/cm 3 Between them.
Comparative example 1
In this comparative example, the same procedure as in example 1 was followed except that ethanol was used as the only dimethyldimethoxysilane, and the content of dimethyldimethoxysilane was changed in the same manner as in example 1, and the results are shown in Table 6.
TABLE 6
The relationship between the viscosity average molecular weight and the ethanol concentration of 0 to 300ppm was linearly fitted to find that y=0.838383 x+258.73, R 2 = 0.9983, linear fitting of the relation between the polymerization activity and the ethanol concentration of 0 to 300ppm revealed that y= -70.517x+37561, r 2 ＝0.9595。
Comparative example 2
In this comparative example, the same procedure as in example 1 was followed except that ethanol was merely modified to dimethyl phthalate, and the content of dimethyl phthalate was changed in the same manner as in example 1, and the results are shown in Table 7.
TABLE 7
The relationship between the viscosity average molecular weight and the ethanol concentration of 0 to 300ppm was linearly fitted to find that y=0.7726x+259.66, R 2 = 0.9983, linear fitting of the above polymerization activity to ethanol concentration of 0 to 300ppm, found y= -78.06x+38764, r 2 ＝0.9475。
As can be seen from tables 6 and 7, in comparative examples 1 to 2, the adjustment of molecular weight was performed using silanes or esters, and although the adjustment was performed to the molecular weight of the ultra-high molecular weight polyethylene, the polymerization activity of the reaction was significantly lowered, which means that longer man-hours were required to obtain a polyethylene of higher molecular weight when the ultra-high molecular weight polyethylene was prepared using the above materials, the cost was significantly increased, and the sensitivity of the adjustment was low.
In the test process, the ultra-high molecular weight viscosity average molecular weight test method comprises measuring the intrinsic viscosity of the polymer by using GB1632.3-2010 and determining the viscosity according to the formula eta=KM η a (K and a are constants), η is viscosity, and the viscosity average molecular weight M is calculated η . Bulk density is tested by adopting the specification in GB/T-1636-2008 and adopting an A-type funnel; the polymerization activity is calculated by adopting the mass ratio of ethylene to catalyst; the particle size D50 is obtained by testing by a laser particle size analyzer method.
The polymerization activity of the catalyst per hour per gram is adopted in the invention, and compared with g.PE/g.cat, the polymerization activity effect of the catalytic reaction can be fed back in time, thereby avoiding the situation that the ultra-high molecular weight can be achieved only by long-time reaction.
The detailed process equipment and process flow of the present invention are described by the above embodiments, but the present invention is not limited to, i.e., it does not mean that the present invention must be practiced depending on the detailed process equipment and process flow. It should be apparent to those skilled in the art that any modification of the present invention, equivalent substitution of raw materials for the product of the present invention, addition of auxiliary components, selection of specific modes, etc., falls within the scope of the present invention and the scope of disclosure.
Claims (25)
1. A method for regulating the molecular weight of ultra-high molecular weight polyethylene, characterized in that the method comprises the steps of:
(1) Mixing a first part of alkyl aluminum and a first part of alkane solvent, and stirring at a first temperature to obtain an alkane solvent in which the alkyl aluminum is dispersed;
(2) Simultaneously introducing a second part of alkyl aluminum with a Z-N catalyst and a second part of alkane solvent into the alkane solvent in which the alkyl aluminum is dispersed, adding alcohol with different mass, and heating to a second temperature; the alcohol accounts for 0.1-300 ppm of the total mass of the alkane solvent;
(3) Introducing ethylene into the system in the step (2), pressurizing, and carrying out polymerization reaction to obtain ultrahigh molecular weight polyethylene with different molecular weights, wherein the ethylene is introduced in two sections, namely a first section and a second section; the flow of ethylene in the first section is 500-700 g/h; the ethylene feed in the first stage is 3 to 5wt% of the total ethylene feed.
2. The method for adjusting molecular weight according to claim 1, wherein the alkyl aluminum is any one of trimethyl aluminum, triethyl aluminum, tripropyl aluminum, triisobutyl aluminum, tri-n-butyl aluminum, triisoamyl aluminum, trihexyl aluminum, triisohexyl aluminum, or diethyl methyl aluminum or a combination of at least two thereof.
3. The method for adjusting molecular weight according to claim 1, wherein the aluminum alkyl is triethylaluminum.
4. The method for adjusting molecular weight according to claim 1, wherein the Z-N catalyst is 0.001 to 0.003% of the total amount of ethylene fed.
5. The method for adjusting molecular weight according to claim 1, wherein the Z-N catalyst accounts for 1 to 10% of the total mass of the aluminum alkyl.
6. The molecular weight adjustment method of claim 1, wherein the alcohol comprises any one or a combination of at least two of methanol, ethanol, propanol, or butanol.
7. The method for regulating molecular weight according to claim 1, wherein the alkane solvent comprises any one or a combination of at least two of alkanes having 5 to 10 carbon atoms.
8. The method of claim 1, wherein the first portion of the alkyl aluminum in step (1) comprises 0.01 to 0.02% by mass of the first portion of the alkane solvent.
9. The method of claim 1, wherein the first temperature is 70 to 80 ℃.
10. The method of claim 1, wherein the stirring time at the first temperature is 0.5 to 1.5 hours.
11. The method according to claim 3 or 4, wherein the first portion of the alkane solvent in the step (1) is 70 to 89% of the total alkane solvent.
12. The method of claim 1, wherein the first portion of the aluminum alkyl comprises 60 to 70% of the total aluminum alkyl.
13. The method of claim 3, wherein the second portion of the alkane solvent in the step (2) is 11 to 30% of the total alkane solvent.
14. The method of claim 1, wherein the second portion of the aluminum alkyls comprises 30 to 40% of the total aluminum alkyls.
15. The method of claim 1, wherein the molar ratio of aluminum to titanium in the total of the Z-N catalyst and the alkylaluminum is 1 (100-500).
16. The method of claim 1, wherein the second temperature is 50 to 65 ℃.
17. The method for regulating molecular weight according to claim 1, wherein the pressure of the polymerization reaction in the step (3) is 0.6 to 0.7MPa.
18. The method of claim 1, wherein the polymerization reaction temperature is 60 to 80 ℃.
19. The method of claim 1, wherein the suction is performed after the polymerization reaction in step (3) is completed.
20. The method of claim 19, wherein the suction pressure is 0.6 to 0.7MPa.
21. The method of claim 19, wherein the time for suction is 5 to 15 minutes.
22. The method according to claim 1, wherein the ethylene flow rate in the step (3) is 500 to 2000g/h.
23. The method according to claim 1, wherein the flow rate of ethylene in the second stage is initially 1500 to 2000g/h, and the flow rate is controlled to maintain the pressure of the polymerization reaction constant after the pressure of the polymerization reaction is reached.
24. The method of claim 1, wherein the ethylene feed in the second stage is 95 to 97wt% of the total ethylene feed.
25. The method for regulating molecular weight according to claim 1, wherein the method for regulating molecular weight comprises the steps of:
(1) Mixing a first part of alkyl aluminum and a first part of alkane solvent, wherein the first part of alkyl aluminum accounts for 0.01-0.02% of the mass of the first part of alkane solvent, stirring for 0.5-1.5 h at 70-80 ℃, the first part of alkane solvent accounts for 70-89% of the total alkane solvent, and the first part of alkyl aluminum accounts for 60-70% of the total alkyl aluminum, so as to obtain the alkane solvent dispersed with the alkyl aluminum;
(2) Simultaneously introducing a second part of alkyl aluminum with a Z-N catalyst and a second part of alkane solvent into the alkane solvent in which the alkyl aluminum is dispersed, wherein the second part of alkane solvent accounts for 11-30% of the total alkane solvent, the second part of alkyl aluminum accounts for 30-40% of the total alkyl aluminum, the molar ratio of aluminum to titanium in the total components of the Z-N catalyst and the alkyl aluminum is 1 (100-500), the Z-N catalyst accounts for 1-10% of the total alkyl aluminum, adding alcohol with the total alkane solvent weight of 0.1-300 ppm, and heating to 50-65 ℃;
(3) Introducing ethylene into the system of the step (2) in two sections, wherein the flow of the ethylene in the first section is 500-700 g/h, and the feeding amount of the ethylene in the first section accounts for 3-5 wt% of the total feeding amount of the ethylene; adjusting the flow rate to a second section, wherein the initial flow rate of ethylene in the second section is 1500-2000 g/h, controlling the flow rate to maintain the pressure of the polymerization reaction constant after reaching the pressure of the polymerization reaction, controlling the feeding amount of ethylene in the second section to account for 95-97 wt% of the total feeding amount of ethylene, and stopping feeding ethylene after controlling the Z-N catalyst to account for 0.001-0.003% of the total feeding amount of ethylene; and after the feeding is finished, maintaining the pressure of the polymerization reaction at 0.6-0.7 MPa and at 60-80 ℃ for polymerization reaction, maintaining the suction pressure at 60-80 ℃ for 5-15 min after the polymerization reaction is finished, decompressing and cooling to obtain the ultra-high molecular weight polyethylene with different molecular weights.
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| CN102617763A (en) * | 2012-03-29 | 2012-08-01 | 中国科学院长春应用化学研究所 | Preparation method of ultrahigh molecular weight polyethylene |
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| CN108203481A (en) * | 2016-12-20 | 2018-06-26 | 中国石油天然气股份有限公司 | The production method of ultra-high molecular weight polyethylene |
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| CN102718901A (en) * | 2012-06-19 | 2012-10-10 | 浙江大学 | Ultrahigh molecular weight polyethylene catalyst preparation method and catalyst prepared by same and application of catalyst |
| CN108203481A (en) * | 2016-12-20 | 2018-06-26 | 中国石油天然气股份有限公司 | The production method of ultra-high molecular weight polyethylene |
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